Atomic transistors based on seamless lateral metal-semiconductor junctions with a sub-1-nm transfer length

Abstract

The edge-to-edge connected metal-semiconductor junction (MSJ) for two-dimensional (2D) transistors has the potential to reduce the contact length while improving the performance of the devices. However, typical 2D materials are thermally and chemically unstable, which impedes the reproducible achievement of high-quality edge contacts. Here we present a scalable synthetic strategy to fabricate low-resistance edge contacts to atomic transistors using a thermally stable 2D metal, PtTe2. The use of PtTe2 as an epitaxial template enables the lateral growth of monolayer MoS2 to achieve a PtTe2-MoS2 MSJ with the thinnest possible, seamless atomic interface. The synthesized lateral heterojunction enables the reduced dimensions of Schottky barriers and enhanced carrier injection compared to counterparts composed of a vertical 3D metal contact. Furthermore, facile position-selected growth of PtTe2-MoS2 MSJ arrays using conventional lithography can facilitate the design of device layouts with high processability, while providing low contact resistivity and ultrashort transfer length on wafer scales.

Improving Contacts and Electrical Performances of Nanofilms of MoS2 Transistors through Ultrastrong vdW Integration with Dirac Semimetal PtTe2

“…It is known that covalent bonding in 2D lateral heterostructures can increase the cohesive coupling and efficiently inject carriers deep into 2D semiconductors, giving high electrical performances. , Similarly, contacts of MoS 2 transistors can be improved by developing a mild covalent functionalization method, which can realize stable carrier doping of 2D materials . Unfortunately, it is difficult to realize covalent contacts in conventional vertical vdW heterostructures because of the bonding-free surface of 2D layered materials and weak vdW interactions.…”

“…31,32 It has been experimentally verified that PtTe 2 as electrodes can reduce contact resistance through an edge-to-edge connection between PtTe 2 and 2D semiconductors. 33,34 Those edge contacts based on a lateral heterostructure synthesized by the CVD route are incompatible with current semiconductor manufacturing processes. 35 More importantly, PtTe 2 possesses an ultrastrong vdW force between interlayers, suggesting that the vertical contact between 2D semiconductors and PtTe 2 is expected to be more efficient.…”

“…Interlayer coupling plays a fundamental role not only in the electronic properties of vdW heterostructures but also in the vdW gap. , Recently, Z. Wu et al demonstrated that nonvolatile memristive forming can eliminate the vdW gap between 2D channels and contact electrodes, thus reducing the contact resistance by at least 1 order of magnitude . Besides the type-I Dirac semimetal represented by graphene, the layered PtTe 2 as a type-II Dirac semimetal is an emerging semimetallic material and has wide-ranging potential applications in mid-infrared and even terahertz photodetection. , It has been experimentally verified that PtTe 2 as electrodes can reduce contact resistance through an edge-to-edge connection between PtTe 2 and 2D semiconductors. , Those edge contacts based on a lateral heterostructure synthesized by the CVD route are incompatible with current semiconductor manufacturing processes . More importantly, PtTe 2 possesses an ultrastrong vdW force between interlayers, suggesting that the vertical contact between 2D semiconductors and PtTe 2 is expected to be more efficient .…”

Modified Spatially Confined Strategy Enabled Mild Growth Kinetics for Facile Growth Management of Atomically‐Thin Tungsten Disulfides

“…The full potentials of these atomically‐thin crystals requires reliable and diversified synthesis of 2D TMDCs, which is essential for the discoveries of their new physics and novel device applications. [ 10 , 11 , 12 , 13 , 14 ] Up to now, chemical vapor deposition (CVD) has been widely applied as a mainstream method for the preparation of electronic grade 2D TMDCs, owing to its great potential in low‐cost and scaled‐up productions. [ 1 , 2 , 15 ] For traditional CVD growth of 2D TMDCs, the metal oxide power MO 3 and chalcogen powder X usually act as reaction sources.…”

“…[ 1 , 2 , 15 ] For traditional CVD growth of 2D TMDCs, the metal oxide power MO 3 and chalcogen powder X usually act as reaction sources. [ 7 , 11 , 12 ] In a CVD system, the X:M ratio of vapor has been verified as a crucial reaction kinetics factor that majorly affects the uniform and reproducible growth of 2D TMDCs products. [ 16 , 17 , 18 , 19 ] However, violent evaporation and large diffusivity discrepancy of metal and chalcogen precursors at elevated temperatures always result in uncontrollable X:M ratio and thus drastic growth kinetics; this phenomenon makes the stable and controllable growth of 2D TMDCs fascinating yet an intractable topic.…”